“Neuromodulation” is the therapeutic alteration of activity in the central, peripheral or autonomic nervous systems, electrically and/or pharmacologically, by means of implanted devices. Implantable medical devices are used to deliver neuromodulation therapy to patients to treat a variety of symptoms or conditions. For example, some the implantable medical devices deliver neurostimulation therapy in the form of electrical pulses. For some conditions, electrical stimulation is performed in combination with drug therapy using implantable drug pumps that deliver drugs to the nerves undergoing neurostimulation.
U.S. Publication No. US2005/0043765 (“765 publication”) Intravascular Electrophysiological System and Methods (filed Jun. 4, 2004 and commonly owned with the present application), which is incorporated herein by reference, describes intravascular systems that may be used to deliver electrical energy to the heart such as for defibrillation, pacing, and/or cardioversion of the heart.
Such systems include at least one housing containing the necessary pulse generator and associated electronics, circuitry and related components, and they optionally include at least one lead carrying some or all of the electrodes needed to deliver the electrical energy to the body. Some or all of these components are positioned within the vasculature, such as in the superior vena cava (“SVC”), the inferior vena cava (“IVC”), the left or right subclavian vein (“LSV” or “RSV”), coronary sinus and/or within other vessels in the venous or arterial system. For some of the implant components (such as the housing and/or lead), anchoring devices may be needed to retain the implant within the vasculature.
U.S. Publication No. 2005/0234431 (“431 publication”), Intravascular Delivery System for Therapeutic Agents (filed Feb. 10, 2005 and commonly owned with the present application), which is incorporated herein by reference, describes systems for intravascular drug delivery system. Certain ones of the embodiments of the described systems include a reservoir implantable within a blood vessel, an intravascular pump fluidly coupled to the reservoir and an anchor 16 expandable into contact with a wall of the blood vessel to retain the system within the vasculature. Delivery conduits 108 (FIG. 11 of the '431 publication) may extend from the reservoir and are positionable at select locations within the vasculature for target drug delivery to select organs or tissues. Throughout this disclosure, the terms “drugs” and “agent” will be used to refer to any substances to be delivered into the body for any purpose including, but not limited to, prophylactic or therapeutic purposes. In some cases, such substances might also be biologic, such as vector-directed or mediated gene therapy, microspheres containing releasable agents, or stem cells modified to express certain proteins or other therapeutic or diagnostic compounds.
As disclosed in each of the above-referenced applications as well as U.S. Publication No. 2006/0217779 Flexible Hermetic Enclosure for Implantable Medical Devices (filed Mar. 24, 2005 and commonly owned with the present application), which is incorporated herein by reference, these types of implantable devices may be long and narrow for implantation into the vascular, and in some cases can be approximately 10-60 cm in length. Such devices are preferably sufficiently flexible to move through the vasculature yet sufficiently rigid to protect the internal components. Certain embodiments described in the above-referenced patent applications build flexibility into the elongate implants by assembling them using a plurality of segments, with each segment defining interior space for components to be housed within it. Each segment may be separately enclosed by its own enclosure, with several such enclosures coupled together to form the implant. The enclosures are interconnected at articulations formed using silicone rubber filler or mechanical bellows.
It is believed that intravascular devices of the type described in the referenced applications may be suitable for use as neuromodulation devices to delivery electrical and/or pharmaceutical therapy to the nervous system.